	function reward($field, $value) {
		$value = (array) $value;
		$ranks = $value['rank'];
		$numbers = $value['number'];
		$result = array();
		foreach ($ranks as $k => $rank) {
			$rank = (int) $rank;
			if($rank < 1 || !is_numeric($numbers[$k])) continue;
			$result[$rank] = $numbers[$k];
		}
		return serialize($result);
	}